1. Field of the Invention
The present invention concerns steam sealing strips for wafer baking plates to laterally seal the wafer baking space formed between two wafer baking plates which are arranged above each other. Steam channels are provided in the steam sealing strips, leading to the outside from the wafer baking space.
2. Description of the Prior Art
In the production of wafers, the dough is poured in strips, with the baking tongs open, onto the lower wafer baking plate; and the baking tongs are subsequently closed. During the closing of the baking tongs, the dough, which as a considerable water content, contacts the hot surfaces of the two wafer baking plates. The water contained in the dough begins to evaporate and distributes the dough over the entire baking space. In order to obtain a sheet of wafers that is homogeneous and has the same mechanical strength even to the corners, it is necessary to pour on slightly more dough than required. This excess dough exits through the steam channels of the steam sealing strips and forms balls of dough at the ends of the channels. While the excess dough remaining in the steam channels is baked and forms so-called dough webs from which the small dough balls are suspended, the balls themselves are not baked but remain mostly in the form of a very sticky mass. The failure of the dough balls to be baked may be attributed primarily, in addition to the absence of baking surfaces in contact with them, to the frequently too low baking temperatures in the baking space of the oven. This is particularly true for electrically heated ovens wherein the heating devices are arranged in the baking plates themselves and the oven space is heated merely by the heat radiated by the baking plates. Furthermore, the steam generated in the baking process must be removed from the oven space, causing the movement of large volumes of air through the oven space. Thus, in the oven space, especially in electrically heated ovens, the temperature necessary to effect baking of the balls of dough is never attained.
The resulting problems stem primarily from the fact that the adhesive balls of dough remain suspended from the rims of the baking plates and do not drop away. This leads, in the course of the process, to an accumulation of balls of dough, which interferes with the degassing process during the baking of the sheets of wafers. Furthermore, the unbaked balls of dough remain suspended on all of the parts inside of the oven space and are, therefore, difficult to remove.
In electrically heated baking ovens, the balls of dough resulting from the individual production runs form a single lump, which dries out during a shutdown of the oven or over an extended period of operation. The lump becomes hard enough so that it can be removed by mechanical means only. This leads to highly expensive cleaning procedures of automatic baking machines and thus to increased labor costs. Even when the unbaked balls of dough separate from the wafer plate and drop into the inside of the automatic machine, they interfere with operation. This is so because, in electrically heated ovens, sliding contacts and bus bars are arranged underneath the baking plates, and the balls of dough dropping onto them glue the contacts and bars together, which leads to an interruption of the current.
Another reason why it is desirable to obtain baked balls of dough is that the unbaked balls of dough spoil rapidly and cannot be utilized further.